Acropora Problem

[phljess]

One of my Acropora Colonies is dying off. It turns light brown on the bottom then starts to recede from the bottom up. It is very dry to the touch when taken out of the tank to frag still living pieces does not produce much slime when out of water. Also polyp extension has been poor for the last couple weeks. I am at a loss on what is the cause. I have inspected it for red bugs but I can not see them with my naked eye. I know what they look like, and I have had the coral for about a year. All other acros are doing fine with good growth.

Here are the stats:

Nitrite-0 ppm
Nitrate>5 ppm
pH 8.2-8.5 through the cycle of a day.
Ammonia-0 ppm
Calcium 400 ppm
Phosphates-0
Alkalinity 2.75-3.0 MeqL
Good variable water flow. About forty times turn over in SPS area of tank.
Temperature is 78-81 degrees throughout day cycle

 

[phljess]

SG. is at 1.025 and photoperiod is 12 hours with 400 watt halides.

 

[NuclearReefs]

Magnesium?
Ph a Little high during the day soo..
You changed anything? adding anything new?
How old are your Halides and what kind are they?

 

[phljess]

Last time I checked, magnesium was within range, a little on the low side but I cannot remember the exact amount. I can check it again tomorrow. I am using 6.5K Iwasaki bulbs. They have about 5 months on them. The recession looks alot like the pic Lunchbucket uploaded. I do not think it is flat worms but I am not sure. I do not see any eggs or worms but I do not have a magnifying glass so they may be there. I have had to frag it to stop the recession and the frags have done well after being taken from the colony. I added a piece of Merulina a couple weeks ago but I do not think it caused the problem.

If there is AEFW will they migrate to my other acros? How should get them out of the tank? However, I would not think it is AEFW's because I have kept the coral for almost a year without problems until about a month ago. I have only added one new acro since I bought the one that is recessing and it does not exhibit this recession.

 

[gemxsps]

Sometimes acro became dead even if every parameter is perfect. Your colony is from aquaculture or wild captive?
Many wild captive can not be adapted in tank and dead. But yor colony comes from aquaculture, it will be good if your parameter is good.

 

[kneepuck]

Alk seems low, shoot for 4-5 meq/L. SPS are funny sometimes. I have them die out for unknown reasons too.

 

[phljess]

This was a wild piece, the strange thing is that it has been in my tank for about 9 months and only started having trouble in the last month. The recession starts at the bottom with a white band then goes to the top rapidly after the base starts to lose its color. It is blotchy as it runs up from the base. I inspected it with a 10X magnifying glass and can not see any red bugs. I have also heard I should keep my Alk at about 3 meq/L when cal is 400. What is everyone else keeping their alk at?

 

[Frankysreef]

wild pieces can be tough....They will be dormant for a while and then if parameters suit them they will grow... or sometimes they will die.